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The cryo-EM structure of OsCyc1 hexamer state
Structural highlights
FunctionCPS4_ORYSJ Catalyzes the conversion of geranylgeranyl diphosphate to the phytoalexin precursor syn-copalyl diphosphate (PubMed:15341631, PubMed:15255861, PubMed:23621683). Required for the biosynthesis of momilactones that exude from roots and act as allelochemicals against lowland weeds in paddy soil (PubMed:23621683).[1] [2] [3] Publication Abstract from PubMedThe large superfamily of labdane-related diterpenoids is defined by the cyclization of linear geranylgeranyl pyrophosphate (GGPP), catalyzed by copalyl diphosphate synthases (CPSs) to form the basic decalin core, the copalyl diphosphates (CPPs). Three stereochemically distinct CPPs have been found in plants, namely (+)-CPP, ent-CPP and syn-CPP. Here, we used X-ray crystallography and cryo-EM methods to describe different oligomeric structures of a syn-copalyl diphosphate synthase from Oryza sativa (OsCyc1), and provided a cryo-EM structure of OsCyc1(D367A) mutant in complex with the substrate GGPP. Further analysis showed that tetramers are the dominant form of OsCyc1 in solution and are not necessary for enzyme activity in vitro. Through rational design, we identified an OsCyc1 mutant that can generate ent-CPP in addition to syn-CPP. Our work provides a structural and mechanistic basis for comparing different CPSs and paves the way for further enzyme design to obtain diterpene derivatives with specific chirality. Structural and functional investigations of syn-copalyl diphosphate synthase from Oryza sativa.,Ma X, Xu H, Tong Y, Luo Y, Dong Q, Jiang T Commun Chem. 2023 Nov 6;6(1):240. doi: 10.1038/s42004-023-01042-w. PMID:37932442[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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